1. Technical Field
This invention relates to a method of controlling the oxygen concentration of a mixture gas containing oxygen, and a system for practicing the method, and more particularly to an oxygen concentration controlling method in which electrochemical means is utilized to automatically control the oxygen concentration in a chamber or the like to a desired value, and to a system for practicing the method.
In scientific experiments such as biological, medical, metallurgical and chemical experiments, it is often required to control the oxygen concentration of an atmosphere to a desired value. For instance, in cultivating cells, the rate of cultivation is closely related to the oxygen concentration. Thus, there has been a strong demand for the provision of a simple method of controlling oxygen concentration.
2. Prior Art
Heretofore, in order to control the oxygen concentration in a chamber, a mixture gas was prepared by mixing oxygen with an inert gas such as nitrogen, argon or helium, or with carbon dioxide until a desired oxygen concentration was obtained, and was supplied into the chamber. In another conventional method, when the oxygen concentration in the chamber was much higher than a predetermined value, inert gas was supplied into the chamber, and when the oxygen concentration was much lower than the predetermined value, oxygen gas was supplied thereinto. However, these conventional methods are disadvantageous in that the gas cylinder operation and gas flow control are troublesome, and the gas used for control is expensive.